After listening to what Lefanen has to say, you will be appointed a quest to collect a small piece of a Kaon Fae Stone, and a Faidarran Guardian Seed. Each with magical properties that will help you in your fight against the headmaster.
The Kaon Stone can be found near rocks that reside in the front area of the building you are standing on. It is a ground spawn that looks like a tiny tablet. I personally found the stone near Ashby (which can be viewed by my picture). From what I saw, only one stone can be up at a time, but once you loot the stone, another one appears in another spot in the front area of that building. So if you have multiple people doing this step, you will each need to collect a stone.
The Faidaaran Guardian Seed drops off of Faidaaran Guardians, which are huge treeants that roam the front of the building. They are level 16 4dot mobs and are very hard to miss (yes, they are huge!). The drop is fairly rare, and may take a bit before everybody on your group has one.
In order to get Tyrnal to give you the hoops, you will have to prove to her that you mean business! How? you ask. By killing 10 students inside of the building that you are standing on, of course! You will not only have to kill the 10 students, but you will also need to chop off their heads and make a nice stack of all 10 of them! Each student will be around level 16 4dot, and with a good group, shouldn't take you that long to pick up all ten.
So you have teleported to Eranir, via Ashby's teleportation services and talked with Eranir. He will inform you that you need something called the Soultrap Scroll which is somewhere hidden inside of the building that you are standing on. Venturing inside the building will be tough, as there are many students, level 15 4dot, that will be waiting to kill you, while you search.
The scroll is a ground spawn and appears randomly throughout the whole building. Once you loot the scroll once, it despawns and reappears in another place inside the building. So if you have multiple people doing this quest with you, you will have to kill through the building a lot in order to find everyone a scroll.
So if you haven't gotten it already, you have to head back to Arlinora's Retreat and search for the real Soultrap Scroll. This scroll is another ground spawn, but this time it always spawns in the same spot. You will always find this scroll in the building with Inquisitor Nolren, Inquisitor Higrel, and Inquisitor Jarcol. It is the building closest to the riftway stone.
After getting Ashby to port you to Inzia, she will talk to you about one of the headmasters and then tell you to collect 15 Decaying Hearts from the undead that surround the building you are standing on.
So drop down to the front of the building and start killing the undead! The undead mobs will be around level 18 4dot, and do have a seldom chance of dropping the decaying heart. My estimate would be a bit over 50% of the time you will see a heart, and each member of your group has a chance of collecting one, each time you kill a mob. After killing the assortment of Undead and collecting your hearts, get Ashby, once again, to teleport you to Inzia for the turn-in.
So head back to Arlinora's Retreat and you will notice Patrolling Watchmen surrounding the outpost. These Watchmen are level 15 2dot and are easily soloable. Each time you kill one you will get an update for your quest, and you will need to kill 10 in order to empower the sickle.
Where is the crystal? You ask. Well, it is actually past all the undead mobs, at the very south corner of the Lyceum (number 6 on my Map). So, fight your way through the Lyceum (or possibly invis) and make your way to the crystal. Once you are there, porting up to the Oculus is just a matter of right clicking the crystal.
When you do port onto the Oculus you will notice that you are standing on the floating island in the sky. You are high enough now that if you fall off of the island, you will fall to your death. You are standing at the beginning of a path that leads up to the Oculus building. On the path, you will notice lots of mobs in the way of your goal. The mobs are an assortment of creatures that are all around level 20 - 21 4dot, and there are plenty to keep you busy, as you fight you way through to the top.